Master the Wipe-on Finish

Make Your Own
You can easily make your own wiping varnish or oil/varnish blend. To make a wiping varnish, thin any oil-based varnish or polyurethane with mineral spirits (paint thinner) until you reach a thinness that’s easy to wipe on. The higher the ratio of finish the faster it will build, so begin with as little as 25 percent mineral spirits and increase the amount if this doesn’t give you enough working time.

To make an oil/varnish blend, mix any brand of oil-based varnish or polyurethane varnish in any proportion with linseed oil or tung oil. The higher the ratio of varnish you use, the glossier, more protective and durable the finish. The higher the ratio of oil you use, the longer the working time.

If the mixture is too thick for your tastes, thin it with mineral spirits. As with wiping varnish, it doesn’t take much thinner to make a big difference. Commercial brands of wiping varnish and oil/varnish blend are thinned far more than they need to be.

How to Choose What to Use
Choosing among these finishes (oil finishes, wiping varnishes and oil/varnish blends) is easy if you know what you’re looking for. Wiping varnish is much more protective and durable (and glossier, unless you use a satin varnish) than the others because it hardens and can be built up on the wood. Blends of oil and varnish are somewhat more protective and durable than oil alone. Though the differences are small by comparison, tung oil is a little more protective than linseed oil, and polyurethane varnish is a little more protective and durable than varnish.

Linseed oil and tung oil add more amber color to wood than varnish or polyurethane. But each colors the wood more than any other finish except amber shellac.

How to Apply
Apply linseed oil, real tung oil and oil/varnish blends in the same manner – wipe or brush the finish onto the wood, keep the surface wet for a few minutes, then wipe off the excess. If the finish bleeds back out of the pores, continue wiping every hour or so until it stops.

Allow overnight drying in a warm room (three days for tung oil), then sand the surface smooth with very fine sandpaper (#280-grit or finer). Apply a second coat and then as many additional coats as you need to achieve the appearance you’re after. Using more than three or four coats is seldom necessary. Continue sanding between coats if the surface isn’t already smooth to the touch.

Wiping varnish can be applied the same way, or it can be applied like full-strength varnish – by brushing and leaving it. You can also brush or wipe on the finish and then partially wipe it off, leaving a thin film. Allow overnight drying after each coat and sand between each coat to remove dust nibs. Apply as many coats as you need to get the appearance you want.

To get a satin sheen without having to rub the finish with fine steel wool, make your own wiping varnish from a satin varnish or polyurethane. Leave a thin film on the surface to get an even satin effect.

Above are a number of commonly available wipe-on finishes. But with the exception of Minwax’s Wipe-On Poly, the labels aren’t helpful. The list will help. Fire SafetyTo avoid the possibility of spontaneous combustion, drape your finish-soaked rags over the rim of a trash can or hang them to dry. Don’t put one rag on top of another. When the rags harden, you can safely throw them away.